Boc-Gly-PEG-endo-BCN is a type of molecule commonly used in pharmaceutical research and development. It is a modified amino acid derivative that contains several functional groups, including a Boc (tert-butyloxycarbonyl) protecting group, a PEG (polyethylene glycol) linker, and an endo-BCN (bicyclononyne) moiety. The Boc group helps protect the amino acid from unwanted reactions, while the PEG linker increases solubility and biocompatibility of the molecule. The endo-BCN group allows for the selective conjugation of the molecule with other molecules of interest, such as drugs or imaging agents, through click chemistry. This unique combination of functional groups makes Boc-Gly-PEG-endo-BCN a versatile tool for drug discovery and development, particularly in the areas of targeted drug delivery and molecular imaging.